syz-fuzzer: use single connection to manager
syz-fuzzer: use single connection to manager

This will simplify gvisor support as it's somewhat problematic
to proxy multiple connections between host and guest.

xairy/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller